Modern destroyers and frigates often perform a cruiser's peacetime role, which invites arguments about what to call them. Their wartime roles also explain why they retain destroyer and frigate labels despite their size. Larger or more varied weapons require sensors and power generation, along with crews and the supplies to sustain them. Propulsion must then move the resulting ship through the water. The hull has to accommodate that combined demand.
Notable Point · 8:33-9:50
Why modern destroyers need cruiser-sized hulls
Peacetime cruising duties invite comparisons with cruisers, while wartime weapons and their supporting systems determine the size of modern destroyers and frigates.